Differentiate between virus, Trojan, worm and spyware. How do they do harm our computer?

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Question : No. 7
Matric no : 21382
Faculty : Faculty Resourse Science and Technology (FSTS)
Email address : luis...@yahoo.com

Differentiate between virus, Trojan, worm and spyware. How do they do
harm our computer?


Virus
A computer virus attaches itself to a program or file enabling it to
spread from one computer to another, leaving infections as it travels.
Like a human virus, a computer virus can range in severity: some may
cause only mildly annoying effects while others can damage your
hardware, software or files.
Almost all viruses are attached to an executable file, which means the
virus may exist on your computer but it actually cannot infect your
computer unless you run or open the malicious program. It is important
to note that a virus cannot be spread without a human action, (such as
running an infected program) to keep it going.

People continue the spread of a computer virus, mostly unknowingly, by
sharing infecting files or sending e-mails with viruses as attachments
in the e-mail.


Trojan Horse

A Trojan Horse is full of as much trickery as the mythological Trojan
Horse it was named after. The Trojan Horse, at first glance will
appear to be useful software but will actually do damage once
installed or run on your computer. Those on the receiving end of a
Trojan Horse are usually tricked into opening them because they appear
to be receiving legitimate software or files from a legitimate
source. When a Trojan is activated on your computer, the results can
vary. Some Trojans are designed to be more annoying than malicious
(like changing your desktop, adding silly active desktop icons) or
they can cause serious damage by deleting files and destroying
information on your system. Trojans are also known to create a
backdoor on your computer that gives malicious users access to your
system, possibly allowing confidential or personal information to be
compromised. Unlike viruses and worms, Trojans do not reproduce by
infecting other files nor do they self-replicate.

Worm
A worm is similar to a virus by design and is considered to be a sub-
class of a virus. Worms spread from computer to computer, but unlike a
virus, it has the capability to travel without any human action. A
worm takes advantage of file or information transport features on your
system, which is what allows it to travel unaided.
The biggest danger with a worm is its capability to replicate itself
on your system, so rather than your computer sending out a single
worm, it could send out hundreds or thousands of copies of itself,
creating a huge devastating effect. One example would be for a worm to
send a copy of itself to everyone listed in your e-mail address book.
Then, the worm replicates and sends itself out to everyone listed in
each of the receiver's address book, and the manifest continues on
down the line.

Due to the copying nature of a worm and its capability to travel
across networks the end result in most cases is that the worm consumes
too much system memory (or network bandwidth), causing Web servers,
network servers and individual computers to stop responding. In recent
worm attacks such as the much-talked-about Blaster Worm, the worm has
been designed to tunnel into your system and allow malicious users to
control your computer remotely.






Spyware
Any software that covertly gathers user information through the user's
Internet connection without his or her knowledge, usually for
advertising purposes. Spyware applications are typically bundled as a
hidden component of freeware or shareware programs that can be
downloaded from the Internet; however, it should be noted that the
majority of shareware and freeware applications do not come with
spyware. Once installed, the spyware monitors user activity on the
Internet and transmits that information in the background to someone
else. Spyware can also gather information about e-mail addresses and
even passwords and credit card numbers.
Spyware is similar to a Trojan horse in that users unwittingly install
the product when they install something else. A common way to become a
victim of spyware is to download certain peer-to-peer file swapping
products that are available today.

Aside from the questions of ethics and privacy, spyware steals from
the user by using the computer's memory resources and also by eating
bandwidth as it sends information back to the spyware's home base via
the user's Internet connection. Because spyware is using memory and
system resources, the applications running in the background can lead
to system crashes or general system instability.

Because spyware exists as independent executable programs, they have
the ability to monitor keystrokes, scan files on the hard drive, snoop
other applications, such as chat programs or word processors, install
other spyware programs, read cookies, change the default home page on
the Web browser, consistently relaying this information back to the
spyware author who will either use it for advertising/marketing
purposes or sell the information to another party.

Licensing agreements that accompany software downloads sometimes warn
the user that a spyware program will be installed along with the
requested software, but the licensing agreements may not always be
read completely because the notice of a spyware installation is often
couched in obtuse, hard-to-read legal disclaimers.



URL: http://www.webopedia.com/DidYouKnow/Internet/2004/virus.asp,
http://www.webopedia.com/TERM/s/spyware.html





Is it important to install antivirus software? Why?

Yes.
Any computer and internet user, regardless of the reasons that they
are online, need to have the latest antivirus software programs
installed on their computer. Even thought most of these programs come
already installed with your computer and are free, antivirus software
is absolutely essential to safe and uninterrupted internet usage. It
also plays and important role in computer safety, as it can protect
your vital documents and files from becoming damaged or lost forever.

How does an antivirus software program detect and eliminate potential
virus threats? This can be accomplished in one of two ways. First, the
computer security program on your PC or laptop scans any files looking
for virus definitions that match a virus dictionary. If a matching
virus is found, the software alerts the user about the virus. The
second method of locating viruses is to identify and suspicious virus
behavior, such as port monitoring, spyware or data capturing. When
these behaviors are detected, the antivirus software springs into
action and gets rid of the infected files.

Every so often, you'll hear on the radio or see on the news about a
potential virus or worm that is spread via email. It may come with a
subject line like "open this to see a funny video". Once the video is
opened and downloaded, the virus infects your computer and starts
eliminating or damaging files. Antivirus software can help minimize
the overall threat that viruses cause. As certain as you would lock
your doors at night, or hide away valuable items in a safe location,
computer safety depends on having antivirus software installed in your
machine.

There are certain free antivirus software programs that you can trust
to safely install and operate on your CPU or laptop. Programs such as
McAfee and Norton are proven and respected names in the computer
security industry. These companies continuously monitor and update
their respective antivirus software applications as new and more
dangerous viruses are released. While the potential for completely
eliminating computer viruses and their ramifications from online users
is remote, having these - and other antivirus programs on your
computer can greatly reduce the risk that viruses can cause.

As with any threatening issue, there's always an element of conspiracy
that's involved, and it's no different with antivirus software
companies. Think about it, if viruses were completely eliminated, then
there would be no longer any need for purchased or free antivirus
software programs? Some people theorize that computer security
companies actually benefit from viruses and they actually keep virus
writers on their payroll! Of course, this has never been proven, but
it would make for an interesting movie.

Regardless of whether or not you believe in conspiracy theories, one
thing is for certain: that computer security is dependent on antivirus
software and vice-versa. New worms and programs are being developed
all the time. Some viruses target specific files, like word documents
or excel spreadsheets. Other more malicious programs can actually shut
your computer right down. However, by installing the latest and most
effective antivirus software programs on your computer or laptop,
security will increase and you'll have peace of mind as a luxury.
Travel and visit some computer retailers in your area to learn more
information on the newest antivirus software programs.



URL: http://www.articlesbase.com/computers-articles/the-importance-of-antivirus-software-138090.html

well done^0^